An international aid agency has found baby formula companies are directly contacting new mothers in developing countries, including China and Pakistan.

Lynne Benson, Save the Children Australia's head of international programs, has told Radio Australia's Connect Asia breast milk substitute companies are particularly targeting mothers in Asia and the Pacific.

"In Asia we've got a rapidly growing economy with an expanding middle class and consequently a very good market to target," she said.

Ms Benson says there is a direct link between the decline in breastfeeding rates in some countries and the infant mortality rate.

She says over a quarter of the mothers surveyed by Save the Children reported being approached directly by representatives of breast milk substitute companies.

"So that's all in complete contravention of the international code that's used to guide the marketing of some of these companies," she said.

Ms Benson says Nestle and Danone are the most commonly mentioned companies in the survey of mothers and health care facility workers.

She says the lives of 800,000 children a year could be saved if they were breastfed in the hours immediately after being born, as their immune systems would be boosted.

"We're calling this the power of the first hour," she said.

"If babies are fed in the first hour it increases their chances of survival by 22 per cent."